Bring a large pot of water to a boil and cook the rice noodles according to package directions until tender; drain and set aside.
In a medium bowl, combine shredded carrots, sliced red bell pepper, sliced Fresno or jalapeño pepper, chopped green onions, shredded cabbage and 2 tablespoons low-sodium soy sauce; toss to coat and set aside.
Heat a large wok or heavy skillet over medium heat. Add the ground beef and season with black pepper; cook, breaking up the meat, until browned, about 5 minutes.
Add the finely chopped lemongrass, grated ginger and minced garlic to the browned beef and cook until fragrant, about 30 seconds to 1 minute.
Stir in 1/3 cup low-sodium soy sauce and 1/3 cup sweet Thai chili sauce, plus 1 cup (one large handful) of fresh basil; bring to a simmer and cook until the sauce reduces slightly and coats the beef, about 3–5 minutes.
Remove the skillet from heat, then stir in the remaining 1 cup fresh basil, lime juice and the handful of cilantro.
To serve, divide the cooked noodles among bowls, top with the saucy basil beef, then add the carrot and pepper salad and fresh mango. Garnish as desired and serve immediately.